1. Field of the Invention
The present invention relates to a liquid crystal display device, and more particularly to a technique suitable for a control of an outer periphery of an orientation film material in applying an orientation film to an inner surface of a substrate of a liquid crystal display panel which constitutes a liquid crystal display device.
2. Description of the Related Art
As a television device or a display device of an information terminal, a liquid crystal display device which uses a liquid crystal display panel sealing a liquid crystal material between a pair of substrates consisting of a first substrate and a second substrate has been widely spreading. Usually, the liquid crystal display panel which constitutes this type of liquid crystal display device includes, on a main surface (inner surface) of one substrate out of a pair of substrates, a plurality of scanning signal lines and a plurality of video signal lines which intersects the plurality of scanning signal lines in an insulating manner. Then, one pixel is formed in a region which is surrounded by two neighboring scanning signal lines and two neighboring video signal lines, wherein a switching element which performs an ON/OFF control for every pixel, a pixel electrode and the like are formed in one pixel. In general, a thin film transistor (TFT) is used as the switching element. Accordingly, one substrate on which the thin film transistors are formed is referred to as a thin-film-transistor substrate (TFT substrate). Further, another substrate which forms a pair with one substrate on which the thin film transistors are formed is referred to as a counter substrate. Still further, when a plurality of color filters which are formed corresponding pixels formed on the TFT substrate are formed on the counter substrate, such a counter substrate is referred to as the color filter substrate (CF substrate).
As the liquid crystal display panel, there have been known a vertical-electric-field-type liquid crystal display panel such as a TN-type liquid crystal display panel or a VA-type liquid crystal display panel and a lateral-electric-field-type liquid crystal display panel which is known as an IPS-type liquid crystal display panel due to the difference in a driving method of pixels. In the vertical-electric-field-type liquid crystal display panel, a counter electrode (also referred to as a common electrode) which faces the pixel electrode of the TFT substrate is arranged on a counter substrate side. Further, in case of the lateral-electric-field-type liquid crystal display panel, the counter electrode is formed on the TFT substrate side on which the pixel electrodes are formed, for example.
The TFT substrate and the counter substrate respectively have an orientation film having a function of controlling the direction (initial orientation) of liquid crystal molecules in a state that no potential difference exists between the pixel electrode and the counter electrode and an arrangement and an inclination of the liquid crystal molecules when the potential difference is generated between the pixel electrode and the counter electrode (liquid crystal orientation control function).
The orientation film is formed on interface between respective main surfaces of the TFT substrate and the counter substrate and a liquid crystal material (a liquid crystal layer) and, an orientation control function is imparted to the orientation film by applying rubbing treatment or polarized light radiation or the like to a surface of a resin film which is formed to cover the whole display region on which pixels are arranged two-dimensionally and is preferably made of polyimide.
The resin film made of polyimide or the like which is formed as the orientation film on the surfaces of respective substrates consisting of the TFT substrate and the counter substrate is formed using a method which is referred to as a aniline printing method. However, recently, there has been proposed a method which forms the orientation film using an inkjet printing method (patent document 1). The ink jet printing method directly applies ink to be formed into the orientation material (orientation film material ink) to the substrate using an ink jet nozzle. The ink jet printing method is an on-contact process and hence, the method has various advantages such as the low contamination of substrate surfaces or the fabrication facility, the reduction of solvent consumption quantity, shortening of process time or the like.
Patent document 1: JP-A-2001-337316